1. Field of the Invention
This invention relates generally to flashlights, and more particularly to special-purpose personal-security flashlights tailored to repetitive use for short intervals when the user wishes to inspect an about-to-be-entered car, front porch, or other relatively small area at relatively close quarters. The invention further particularly relates to flashlights that are sufficiently compact to be carried in a purse.
2. Prior Art
Standard six-volt flashlights are impractical for personal-security use as just described, for two reasons. First, they are far too large and heavy.
Second, they cast a beam of light that is narrowly constrained--usually by a silvered, shaped reflector behind the flashlight bulb--so as to illuminate an area the size of a person at, say, forty to sixty feet. Such a beam is too narrow for ready use at close range to determine at a glance whether a person is present in the area of interest, because it only illuminates a small part of a person at close range. By "close range" I mean, for example, four to fifteen feet, or twenty feet at the most. At close range such a narrow beam must be played about the area of interest while looking carefully to visually integrate the information returned.
Another disadvantage of such a beam is that the internal components of the bulb are often imaged by the reflector at some distance from the flashlight, so that shadows are projected forwardly with the beam. These shadows of the filament and other internal bulb parts are often confusing or at least distracting.
The bright, narrow "flare" area of such a standard-flashlight beam is surrounded by a much wider cone of "wash" light. This part of the beam results primarily from the light emanating in a forward direction from the bulb directly--that is to say, not reflected by the reflector behind the bulb. This wider cone, however, is much too dim to be effective, especially because the contraction of the human iris in response to the bright central flare renders the eye insensitive to the information picked up in the "wash" part of the light beam.
Thus standard full-power flashlights are unsuited for examining close quarters about to be entered. A great variety of purse-size flashlights has been introduced in attempts to satisfy the demand for such effective personal precautions. Needless to say, modern urban conditions have enormously increased this demand.
Some of these miniature flashlights are of the well-known "penlight" type--a small bulb, generally two or at most three penlight batteries, and virtually no effective reflector. More-recently introduced models are of a flattened, broader shape only slightly larger than a cigarette pack, with the light and a small reflector on the end or at a corner. These miniature lamps of course overcome the drawbacks of size and weight mentioned earlier. None of these small flashlights, however, is effective in meeting the demand. The reasons are that they are all underpowered, or have undersized light collector/reflectors, or more commonly both--and consequently cast a beam of light that is far too dim to be of real use--and furthermore they are like the full-size lamps in that they cast a beam that is too narrow.